The Road to Gehenna is a DLC add on to The Talos Principle: adding more levels and a new story arc. The tools you have at your disposal to solve the puzzles are the same as previously but instead of collecting sigils you are now freeing other trapped creatures.
(Before I go any further with this review can I please ask that anyone reading this that has yet to play The Talos Principle please go and purchase it immediately. It was one of, if not the, best games of last year and a really surprising and deep puzzle game.)
The additional levels start at quite a high level of difficulty compared to the early levels of the original game, so I would recommend you finish the main game first. That said I am glad the difficulty starts at the level it does, and that all tools are unlocked at the start, as for someone who has played a great deal of the main game I feel like I am really getting my money’s worth by not having to pay for hand holding tutorials.
Honestly the only real criticism I have of this DLC is that the areas are a little similar in style to the original and it would have been nice to explore some different environments.
This game looks beautiful, plays fantastically, makes you think, gives you an immense sense of achievement when you finally crack a puzzle and continues to devise new challenges. The game achieves all this while dealing with complex philosophical themes like what it means to be alive and the true meaning and price of freedom.
Please, please, please give this game and this fantastic DLC a try, an incredible experience and a wonderful achievement.